warm-up at meets

Every single time I practice in the pool I start off in a weird way - as if my muscles are asleep or something(I feels like I do not move what my potential allows me) and only some time throught he work-out it clicks and I start swimming faster , easier and smoother.That probably is nothing strange, 'cause obviously muscles need some warm-p first. That brings me to the following question: at meets(any level - up to Olympics) do swimmers prefer to warm up somehow(maybe go for a short swim) and is that even possible to do, i.e. are there usually certain areas for that?